Method for Accessing Access Point by Station Device, Device, and System

ABSTRACT

Embodiments provide a method for accessing an access point by a station device, a device, and a system. A station device selects a master access point from multiple access points according to channel quality and accesses the master access point, and sends information about remaining access points to the master access point, so that the master access point selects a slave access point according to the information about the remaining access points. In this way, the master access point coordinates with the slave access point to perform data transmission with the station device.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.15/174,752, filed on Jun. 6, 2016, which is a continuation ofInternational Application No. PCT/CN2013/088799, filed on Dec. 6, 2013.All of the afore-mentioned patent applications are hereby incorporatedby reference in their entireties.

TECHNICAL FIELD

Embodiments relate to communications technologies, and in particular, toa method for accessing an access point by a station device, a device,and a system.

BACKGROUND

With the development of communications technologies, intelligentterminals, such as portable computers and smart phones, become morepopular, and these intelligent mobile terminals basically all support awireless local area network (WLAN) technology. Moreover, due to lowcosts, a WLAN network attracts increasingly more users to choose theWLAN network for data service interaction; therefore, the WLANtechnology based on an IEEE 802.11 standard is widely used.

With the rapid development of the WLAN technology, Wireless Fidelity(WiFi) is increasingly widely used, wireless homes and wireless citiesgradually come true, and therefore, a deployment density of accesspoints (AP) increases rapidly. In the prior art, even if in an areahaving a relatively large deployment density of APs, only one AP canaccess, in a contention manner, a channel through carrier sense multipleaccess with collision avoid (CSMA/CA) each time, and as a result,spectrum resources cannot be fully used, and usage efficiency of channelresources is reduced.

SUMMARY

In view of this, embodiments provide a method for accessing an accesspoint by a station device, a device, and a system, so as to improveusage efficiency of spectrum resources, and increase a networkthroughput.

According to a first aspect, an embodiment provides a method foraccessing an access point by a station device. The method includesacquiring, by a station device, channel quality information of multipleaccess points. The method also includes determining, by the stationdevice, a master access point from the multiple access points accordingto the channel quality information of the multiple access points, andaccessing the master access point. The method also includes sending, bythe station device, information about remaining access points in themultiple access points except the master access point to the masteraccess point, so that the master access point determines a slave accesspoint according to the information about the remaining access points andcoordinates with the slave access point to perform data transmissionwith the station device.

With reference to the first aspect, in a first possible implementationmanner of the first aspect, if the station device does not access themaster access point successfully, the station device determines that anaccess point, whose channel quality is lower than channel quality ofonly the master access point, in the multiple access points is a newmaster access point and the station device accesses the new masteraccess point.

With reference to the first aspect or the first possible implementationmanner of the first aspect, in a second possible implementation mannerof the first aspect, the method includes: acquiring, by a stationdevice, channel quality information of multiple access points,determining, by the station device, the master access point from themultiple access points according to the channel quality information ofthe multiple access points, and accessing the master access point; andsending, by the station device, the information about the remainingaccess points in the multiple access points except the master accesspoint to the master access point, so that the master access pointdetermines the slave access point according to the information about theremaining access points and coordinates with the slave access point toperform data transmission with the station device.

With reference to the second possible implementation manner of the firstaspect, in a third possible implementation manner of the first aspect,the acquiring, by a station device, channel quality information ofmultiple access points specifically includes: periodically scanning, bythe station device, access points according to a preset scanning periodt_(s), and acquiring the channel quality information of the multipleaccess points.

With reference to the third possible implementation manner of the firstaspect, in a fourth possible implementation manner of the first aspect,the determining, by the station device, a master access point from themultiple access points according to the channel quality information, andaccessing the master access point specifically includes: after acquiringthe channel quality information of the multiple access points at a timeinterval t_(s), reselecting, by the station device, a new master accesspoint from the multiple access points and accessing the new masteraccess point; and the sending, by the station device, information aboutremaining access points in the multiple access points except the masteraccess point to the master access point specifically includes: afterreselecting the new master access point at a time interval t_(s) andaccessing the new master access point, sending, by the station device,information about remaining access points in the multiple access pointsexcept the new master access point to the new master access point.

With reference to the third possible implementation manner of the firstaspect, in a fifth possible implementation manner of the first aspect,t_(s)=j×t_(b), where j is a positive integer, and t_(b) is a beaconperiod.

With reference to the third possible implementation manner of the firstaspect, in a sixth possible implementation manner of the first aspect,the acquiring, by a station device, channel quality information ofmultiple access points further includes: if a change value betweenchannel quality of multiple access points that is acquired in a currentscan and channel quality of multiple access points that is acquired in aprevious scan is greater than or equal to a first set range, shorteningthe scanning period; or if channel quality change values of multipleaccess points, which are acquired in n consecutive scans, are less thanthe first set range, prolonging the scanning period, where n is aninteger greater than or equal to 1.

With reference to the sixth possible implementation manner of the firstaspect, in a seventh possible implementation manner of the first aspect,a prolonged scanning period is an integer multiple of the scanningperiod, and is not greater than a preset maximum scanning interval.

With reference to the first aspect or any one of the first possibleimplementation manner to the seventh possible implementation manner, inan eighth possible implementation manner of the first aspect, theinformation about the remaining access points includes basic service setidentifiers of the remaining access points and/or channel qualityinformation of the remaining access points.

With reference to the first aspect or any one of the first possibleimplementation manner to the eighth possible implementation manner, in aninth possible implementation manner of the first aspect, the channelquality information includes at least one or more of the following: areceived signal to noise indicator (RSNI), a received signal strengthindicator (RSSI), a beacon received signal strength indicator (BeaconRSSI), a beacon signal to noise ratio (Beacon SNR), a data framereceived signal strength indicator (Data Frame RSSI), and a data framesignal to noise ratio (Data Frame SNR).

According to a second aspect, an embodiment provides a method foraccessing an access point by a station device. The method includesreceiving, by a master access point, information, which is sent by astation device accessing the master access point, about remaining accesspoints in multiple access points except the master access point, wherethe master access point is determined by the station device according tochannel quality information of the multiple access points that isacquired by the station device. The method also includes selecting, bythe master access point, a slave access point from the remaining accesspoints according to the information about the remaining access points.The method also includes coordinating, by the master access point, withthe slave access point to perform data transmission with the stationdevice.

With reference to the second aspect, in a first possible implementationmanner of the second aspect, before the coordinating, by the masteraccess point, with the slave access point to perform data transmissionwith the station device, the method further includes: establishing aninterface, which is for exchange of coordination information, betweenthe master access point and the slave access point.

With reference to the second aspect or the first possible implementationmanner of the second aspect, in a second possible implementation mannerof the second aspect, after the selecting, by the master access point, aslave access point from the remaining access points according to theinformation about the remaining access points, the method furtherincludes: updating, by the master access point, local secondcoordination cluster information, where the second coordination clusterinformation includes information about the station device andinformation about the slave access point; and sending, by the masteraccess point, first coordination cluster information to the stationdevice, where the first coordination cluster information includesinformation about the master access point and the information about theslave access point, so that the station device updates local firstcoordination cluster information according to the first coordinationcluster information, and performs data transmission with the masteraccess point and the slave access point according to updated firstcoordination cluster information.

With reference to the second aspect or either of the first possibleimplementation manner and the second possible implementation manner ofthe second aspect, in a third possible implementation manner, theinformation about the remaining access points includes basic service setidentifiers of the remaining access points and/or channel qualityinformation of the remaining access points; and when the informationabout the remaining access points includes the basic service setidentifiers of the remaining access points, the selecting, by the masteraccess point, a slave access point from the remaining access pointsaccording to the information about the remaining access points isspecifically: selecting, by the master access point, an access point,which is in a same basic service set, as the slave access pointaccording to the basic service set identifiers of the remaining accesspoints.

With reference to the second aspect or either of the first possibleimplementation manner and the third possible implementation manner ofthe second aspect, in a fourth possible implementation manner, thechannel quality information includes at least one or more of thefollowing: a received signal to noise indicator (RSNI), a receivedsignal strength indicator (RSSI), a beacon received signal strengthindicator (Beacon RSSI), a beacon signal to noise ratio (Beacon SNR), adata frame received signal strength indicator (Data Frame RSSI), and adata frame signal to noise ratio (Data Frame SNR).

According to a third aspect, an embodiment provides a station device.The device includes a detector, configured to acquire channel qualityinformation of multiple access points. The device also includes aprocessor, configured to determine a master access point from themultiple access points according to the channel quality information ofthe multiple access points, and access the master access point. Thedevice also includes a transceiver, configured to send information aboutremaining access points in the multiple access points except the masteraccess point to the master access point, so that the master access pointdetermines a slave access point according to the information about theremaining access points and coordinates with the slave access point toperform data transmission with the station device.

With reference to the third aspect, in a first possible implementationmanner of the third aspect, if the station device does not access themaster access point successfully, the processor is further configured todetermine that an access point, whose channel quality is lower thanchannel quality of only the master access point, in the multiple accesspoints is a new master access point and the station device accesses thenew master access point.

With reference to the third aspect or the first possible implementationmanner of the third aspect, in a second possible implementation mannerof the third aspect, after sending the information about the remainingaccess points in the multiple access points except the master accesspoint to the master access point, the transceiver is further configuredto receive first coordination cluster information sent by the masteraccess point, where the first coordination cluster information includesinformation about the master access point and information about theslave access point; and the processor is further configured to updatelocal first coordination cluster information according to the receivedfirst coordination cluster information, so as to perform datatransmission with the master access point and the slave access pointseparately according to updated local first coordination clusterinformation.

With reference to the second possible implementation manner of the thirdaspect, in a third possible implementation manner of the third aspect,the detector is specifically configured to periodically scan accesspoints according to a preset scanning period t_(s), and acquire thechannel quality information of the multiple access points.

With reference to the third possible implementation manner of the thirdaspect, in a fourth possible implementation manner of the third aspect,the processor is specifically configured to: after the channel qualityinformation of the multiple access points is acquired at a time intervalt_(s), reselect a new master access point from the multiple accesspoints and access the new master access point; and the transceiver isspecifically configured to: after the new master access point isreselected at a time interval t_(s) and the new master access point isaccessed, send information about remaining access points in the multipleaccess points except the new master access point to the new masteraccess point.

With reference to the third possible implementation manner of the thirdaspect, in a fifth possible implementation manner of the third aspect,t_(s)=j×t_(b), where j is a positive integer, and t_(b) is a beaconperiod.

With reference to the third possible implementation manner of the thirdaspect, in a sixth possible implementation manner of the third aspect,the processor is further configured to: if a change value betweenchannel quality of multiple access points that is acquired in a currentscan and channel quality of multiple access points that is acquired in aprevious scan is greater than or equal to a first set range, shorten thescanning period; or, if channel quality change values of multiple accesspoints, which are acquired in n consecutive scans, are less than thefirst set range, prolong the scanning period, where n is an integergreater than or equal to 1.

With reference to the sixth possible implementation manner of the thirdaspect, in a seventh possible implementation manner of the third aspect,a prolonged scanning period is an integer multiple of the scanningperiod, and is not greater than a preset maximum scanning interval.

With reference to the third aspect or any one of the first possibleimplementation manner to the seventh possible implementation manner, inan eighth possible implementation manner of the third aspect, theinformation about the remaining access points includes basic service setidentifiers of the remaining access points and/or channel qualityinformation of the remaining access points.

With reference to the third aspect or any one of the first possibleimplementation manner to the eighth possible implementation manner, in aninth possible implementation manner of the third aspect, the channelquality information includes at least one or more of the following: areceived signal to noise indicator (RSNI), a received signal strengthindicator (RSSI), a beacon received signal strength indicator (BeaconRSSI), a beacon signal to noise ratio (Beacon SNR), a data framereceived signal strength indicator (Data Frame RSSI), and a data framesignal to noise ratio (Data Frame SNR).

According to a fourth aspect, embodiments further provide an accesspoint. The access point includes a transceiver, configured to receiveinformation, which is sent by a station device accessing a master accesspoint, about remaining access points in multiple access points exceptthe master access point, where the master access point is determined bythe station device according to channel quality information of themultiple access points that is acquired by the station device. Theaccess point also includes a processor, configured to select a slaveaccess point from the remaining access points according to theinformation about the remaining access points, where the transceiver isfurther configured to coordinate with the slave access point to performdata transmission with the station device.

With reference to the fourth aspect, in a first possible implementationmanner of the fourth aspect, before coordinating with the slave accesspoint to perform data transmission with the station device, thetransceiver is further configured to establish an interface, which isfor exchange of coordination information, between the transceiver andthe slave access point.

With reference to the fourth aspect or the first possible implementationmanner of the fourth aspect, in a second possible implementation mannerof the fourth aspect, after the transceiver selects the slave accesspoint from the remaining access points according to the informationabout the remaining access points, the processor is further configuredto update local second coordination cluster information, where thesecond coordination cluster information includes information about thestation device and information about the slave access point. Thetransceiver is further configured to send first coordination clusterinformation to the station device, where the first coordination clusterinformation includes information about the master access point and theinformation about the slave access point, so that the station deviceupdates local first coordination cluster information according to thefirst coordination cluster information, and performs data transmissionwith the master access point and the slave access point separatelyaccording to updated local first coordination cluster information.

With reference to the fourth aspect or either of the first possibleimplementation manner and the second possible implementation manner ofthe fourth aspect, in a third possible implementation manner, theinformation about the remaining access points includes basic service setidentifiers of the remaining access points and/or channel qualityinformation of the remaining access points. The processor isspecifically configured to select an access point, which is in a samebasic service set, as the slave access point according to the basicservice set identifiers of the remaining access points.

With reference to the fourth aspect or either of the first possibleimplementation manner and the third possible implementation manner ofthe second aspect, in a fourth possible implementation manner, thechannel quality information includes at least one or more of thefollowing: a received signal to noise indicator (RSNI), a receivedsignal strength indicator (RSSI), a beacon received signal strengthindicator (Beacon RSSI), a beacon signal to noise ratio (Beacon SNR), adata frame received signal strength indicator (Data Frame RSSI), a dataframe signal to noise ratio (Data Frame SNR), load information of anaccess point, and information about historical access to an access pointby the station device.

According to a fifth aspect, an embodiment further provides amulti-access point coordination system, including a station device andan access point, where the access point includes a master access pointand a slave access point, where the station device is configured toacquire channel quality information of multiple access points, determinethe master access point from the multiple access points according to thechannel quality information of the multiple access points, access themaster access point, and send information about remaining access pointsin the multiple access points except the master access point to themaster access point. The master access point is configured to receivethe information about the remaining access points that is sent by thestation device, and determine the slave access point according to theinformation about the remaining access points. The master access pointand the slave access point are configured to coordinate to perform datatransmission with the station device.

With reference to the fifth aspect, in a first feasible implementationmanner of the fifth aspect, the system further includes: a timingserver, configured to generate a global clock, and provide the globalclock to the master access point and the slave access point, so that themaster access point synchronizes with the slave access point.

With reference to the fifth aspect or the first feasible implementationmanner, in a second feasible implementation manner of the fifth aspect,the master access point and the slave access point are furtherconfigured to exchange channel state measurement information of thestation device by using an interface that is for exchange ofcoordination information.

With reference to the fifth aspect, the first feasible implementationmanner, or the second feasible implementation manner, in a thirdfeasible implementation manner of the fifth aspect, the master accesspoint and the slave access point are further configured to share, byusing an interface for exchange of coordinatedly transmitted data, datato be communicated with the station device.

According to the method for accessing an access point by a stationdevice, the device, and the system that are provided in the embodimentsof the present invention, a station device selects a master access pointfrom multiple access points according to channel quality and accessesthe master access point, and sends information about remaining accesspoints to the master access point, so that the master access pointselects a slave access point according to the information about theremaining access points. In this way, the master access pointcoordinates with the slave access point to perform data transmissionwith the station device, which improves usage efficiency of spectrumresources, and increases a network throughput.

BRIEF DESCRIPTION OF THE DRAWINGS

To describe the technical solutions in the embodiments of the presentinvention more clearly, the following briefly introduces theaccompanying drawings required for describing the embodiments.Apparently, the accompanying drawings in the following description showmerely some embodiments of the present invention, and persons ofordinary skill in the art may still derive other drawings from theseaccompanying drawings without creative efforts.

FIG. 1 is a network architectural diagram of a multi-access pointcoordination system according to an embodiment;

FIG. 2 is a state switching diagram of an access point in a multi-accesspoint coordination system;

FIG. 3 is a flowchart of a method for accessing an access point by astation device according to an embodiment;

FIG. 4 is a flowchart of a method for accessing an access point by astation device according to another embodiment;

FIG. 5 is a signaling flowchart of selecting a master access point by aSTA in a method for accessing an access point by a station deviceaccording to another embodiment;

FIG. 6 is a signaling flowchart of selecting a slave access point in amethod for accessing an access point by a station device according toanother embodiment;

FIG. 7 is a flowchart of a method for accessing an access point by astation device according to another embodiment;

FIG. 8 is a schematic diagram of coordinating, by access points, tocommunicate with a STA according to another embodiment;

FIG. 9 is a schematic diagram of a scanning interval of a STA in amethod for accessing an access point by a station device according to anembodiment;

FIG. 10 is a schematic structural diagram of a station device accordingto an embodiment;

FIG. 11 is a schematic structural diagram of an embodiment of an accesspoint;

FIG. 12 is a schematic structural diagram of a station device accordingto another embodiment; and

FIG. 13 is a schematic structural diagram of an embodiment of an accesspoint.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

To make the objectives, technical solutions, and advantages of thepresent invention clearer, the following further describes the presentinvention in detail with reference to the accompanying drawings.Apparently, the described embodiments are merely some but not all of theembodiments of the present invention. All other embodiments obtained bypersons of ordinary skill in the art based on the embodiments of thepresent invention without creative efforts shall fall within theprotection scope of the present invention.

FIG. 1 is a network architectural diagram of a multi-access pointcoordination system according to an embodiment. Based on requirements ofimproving spectrum usage, reducing interference, and increasing anetwork throughput, this embodiment provides an architecture in whichAPs coordinate to perform data transmission and interference management.

The system includes: a station device and an access point, and theaccess point includes a master access point and a slave access point.The station device is configured to acquire channel quality informationof multiple access points, determine the master access point from themultiple access points according to the channel quality information ofthe multiple access points, access the master access point, and sendinformation about remaining access points in the multiple access pointsexcept the master access point to the master access point. The masteraccess point is configured to receive the information about theremaining access points that is sent by the station device, anddetermine the slave access point according to the information about theremaining access points. The master access point and the slave accesspoint are configured to coordinate to perform data transmission with thestation device.

As shown in FIG. 1, an AP 1 is a master access point, and an AP 2 is aslave access point. The station device includes a STA 1, a STA 2, a STA3, and a STA 4, and the foregoing entities can support coordinationbetween the APs. The AP 1 and the AP 2 may exchange schedulinginformation and channel state information (CSI) measurement informationof a coordinating STA by using an IE-CS interface, and may also share,by using an interface for exchange of coordinatedly transmitted data(IE-CD), data to be communicated with the coordinating STA, supportnetwork multi-input multi-output (network MIMO), and perform mediumaccess control (MAC) service data unit (MSDU) exchange.

Further, a timing server and an interface for exchange of timing (IE-T)may be set in the system. The timing server is configured to generate aglobal clock, and all APs connected to the timing server may performtiming by using the interface for exchange of timing (IE-T). That is,the timing server may provide the global clock for these APs, so as tosynchronize coordinating APs. The timing server may be an independententity, or may be integrated into an AP.

Both the AP 1 and the AP 2 can keep synchronous with the timing serverby using the IE-T interface; both the AP 1 and the AP 2 can negotiateand coordinate with other APs, perform coordination transmissiondownstream, and perform joint reception upstream.

Both the AP 1 and the AP 2 can maintain coordination clusterinformation, which includes list information of a coordinating AP andlist information of a coordinating STA.

Both the AP 1 and the AP 2 can exchange coordination information byusing the IE-CS interface, where the coordination information includesCSI measurement information of a STA participating in coordination andscheduling information of an AP participating in coordination.

Both the AP 1 and the AP 2 can share transmit data by using theinterface for exchange of coordinatedly transmitted data (IE-CD) whenthe AP 1 and the AP 2 perform coherent transmission.

The AP 1 and the AP 2 each can schedule a STA associated with each ofthe AP 1 and the AP 2, especially in an upstream process.

Persons skilled in the art should understand that the AP 1 and the AP 2may further have all functions, which are specified in the prior art andexisting standards, of an AP.

Switching of the AP 1 and the AP 2 between several states is shown inFIG. 2. According to a function and a definition of an AP entity, basedon an association state between a STA and an AP, the AP may beclassified into a master AP and a slave AP; based on an AP coordinationtransmission manner, the AP may be classified into a signal AP and aninterferer AP.

An AP associated with a target STA is a master AP. The target STAexchanges control signaling with the master AP, and the master AP isresponsible for scheduling the STA associated with the master AP. An APthat is not associated with the STA but is a coordinating AP is a slaveAP. The slave AP participates in coordination transmission performed onthe target STA. The target STA needs to measure CSI of the slave AP.

Even though the slave AP coordinates with the master AP, if the slave APinterferes with the target STA, the slave AP is also an interferer AP.

In the state switching diagram in FIG. 2, the master AP and the slave APare distinguished and switched according to whether an AP is associatedwith the target STA. In all coordinating APs, an AP associated with thetarget STA is a master AP; an AP that is not associated with the targetSTA is a slave AP. State switching between the master AP and the slaveAP is performed as an association state between an AP and an STA isswitched.

The signal AP and the interferer AP are distinguished according towhether an AP sends data to the target STA. Switching between the signalAP and the interferer AP is performed as a coordination transmissionmode and the master AP are changed.

For example, for coordinated beamforming (CBF), an interferer AP may bea signal AP in joint transmission (JT). In addition, because the masterAP is switched into the slave AP, the signal AP in CBF is also changedto an interferer AP in this case. Generally, a master AP is also asignal AP. For JT, a slave AP may also be a signal AP. For CBF andinterference alignment (Interference Alignment, IA), a slave AP is aninterferer AP.

The STA 1, the STA 2, the STA 3, and the STA 4 each can select acandidate coordinating AP, and feed back the information to the masterAP.

The STA 1, the STA 2, the STA 3, and the STA 4 each can measure and feedback CSI of the coordinating AP. Besides, the STA 1, the STA 2, the STA3, and the STA 4 each should have all functions, which are specified inthe prior art and existing standards, of a STA.

This embodiment provides methods and processes for associating with anAP by a STA and for selecting and forming an AP coordination cluster,which resolves a problem that coordination between multiple APs cannotbe performed by using an existing mechanism in a WLAN. The method andsystem that are provided in this embodiment can support coordination andinterference management of multiple APs in an OBSS scenario in a WLAN.The system provided in this embodiment can support synchronization ofmultiple APs in a WLAN by using an introduced timing server entity andIE-T interface. In addition, in the solutions of the present invention,a master AP is selected and associated, a slave AP is selected, acoordination cluster is formed, and a maintaining process of the masterAP and the slave AP is performed, so that it is resolved that which APsare used to serve which STAs at which time, and coordination betweenmultiple APs can be supported. In this embodiment, a forming andmaintaining process of a coordination cluster of the master AP and theslave AP can effectively reduce system overheads, and it is ensured thata change of an AP in the coordination cluster is responded in time;coordination between multiple APs is supported, so that interference canbe effectively suppressed, usage efficiency of spectrums can beimproved, and a network throughput can be increased.

FIG. 3 is a flowchart of a method for accessing an access point by astation device according to an embodiment. The method described in thisembodiment is a processing procedure on a station device side, andincludes the following steps.

Step 11: A station device acquires channel quality information ofmultiple access points.

Step 12: The station device determines a master access point from themultiple access points according to the channel quality information ofthe multiple access points, and accesses the master access point.

Step 13: The station device sends information about remaining accesspoints in the multiple access points except the master access point tothe master access point, so that the master access point determines aslave access point according to the information about the remainingaccess points and coordinates with the slave access point to performdata transmission with the station device.

The multiple access points refer to access points whose channel qualityinformation may be monitored by the station device. Optionally, thechannel quality information may include at least one or more of thefollowing: a received signal to noise indicator (RSNI), a receivedsignal strength indicator (RSSI), a Beacon RSSI, a Beacon SNR, a DataFrame RSSI, and a Data Frame SNR.

Specifically, the beacon received signal strength indicator (BeaconRSSI) is signal strength of a beacon frame received on a channel, and isin units of dBm. Beacon RSSIs obtained by processing a latest receivedsignal by different manufacturers by using different smoothing functionsmay be different.

The beacon signal to noise ratio (Beacon SNR) is a signal to noise ratioof a received beacon frame, and is in units of dB. Beacon signal tonoise ratios obtained by processing a latest received signal bydifferent manufacturers by using different smoothing functions may bedifferent.

The data frame received signal strength indicator (Data Frame RSSI) isreceived signal strength of a data frame received from a network, and isin the unit of dBm. Data Frame RSSIs obtained by processing a latestreceived signal by different manufacturers by using different smoothingfunctions may be different.

The data frame signal to noise ratio (Data Frame SNR) is a signal tonoise ratio of a received data frame, and is in the unit of dB. DataFrame SNRs obtained by processing a latest received signal by differentmanufacturers by using different smoothing functions may be different.

Further, the station device may further acquire load information of anAP, information about historical access to the AP by a STA, and thelike. The station device may further determine the master access pointor the slave access point according to the channel quality informationand with reference to the load information or, for example, accessinformation. The information about historical access to the AP by a STArefers to that, if the STA currently selects an AP 1 as the master AP,and the STA was associated with an AP 2 or an AP 2 was a master AP ofthe STA, the AP 2 may be preferentially selected as the slave AP tocoordinate with the AP 1 to perform data transmission.

The station device may select an access point having best channelquality as the master access point and access the master access point.It should be noted that, if the station device does not access themaster access point successfully, the station device may use an accesspoint, whose channel quality is lower than channel quality of only themaster access point, in the multiple access points as the master accesspoint, and access the master access point.

The station device may send the information about the remaining accesspoints in the multiple access points except the master access point tothe master access point, so that the master access point may determinethe slave access point according to the information about the remainingaccess points and coordinate with the slave access point to perform datatransmission with the station device. The information about theremaining access points may include basic service set identifiers of theremaining access points and/or channel quality information of theremaining access points; if the information about the remaining accesspoints includes the basic service set identifiers of the remainingaccess points, the master access point may select an access point, whichis in a same basic service set, as the slave access point according tothe basic service set identifiers of the remaining access points.

Optionally, after sending the information about the remaining accesspoints in the multiple access points except the master access point tothe master access point, the station device may further receive firstcoordination cluster information sent by the master access point, wherethe first coordination cluster information includes information aboutthe master access point and information about the slave access point;the station device may update local first coordination clusterinformation according to the received first coordination clusterinformation, so as to perform data transmission with the master accesspoint and the slave access point separately according to updated localfirst coordination cluster information.

Optionally, a process of acquiring, by the station device, the channelquality information of the multiple access points may be performedperiodically, a scanning period t_(s) may be preset, and the stationdevice may periodically scan access points, and acquire the channelquality information of the multiple access points.

It should be noted that multiple access points that are scanned eachtime all refer to access points whose channel quality can be monitoredby the station device. Therefore, access points involved in each scanmay be exactly the same, or may be different.

It may be understood that, after acquiring the channel qualityinformation of the multiple access points at a time interval t_(s), thestation device may reselect a new master access point from the multipleaccess points and access the new master access point. Further, thestation device may further send information about remaining accesspoints in the multiple access points except the new master access pointto the new master access point, so that the new master access pointreselects a slave access point.

Optionally, whether to adjust the scanning period may be determinedaccording to a status of channel quality of multiple access points thatare scanned each time, so that the scanning period is prolonged when thechannel quality of the scanned access points changes relativelyslightly, which avoids changing the master access point and the slaveaccess point frequently; the scanning period is shortened when thechannel quality of the scanned access points changes relatively greatly,so as to change the master access point and the slave access point intime.

Specifically, if a change value between channel quality of multipleaccess points that is acquired in a current scan and channel quality ofmultiple access points that is acquired in a previous scan is greaterthan or equal to a first set range, the scanning period is shortened;or, if channel quality change values of multiple access points, whichare acquired in n consecutive scans, are less than the first set range,the scanning period is prolonged, where n is an integer greater than orequal to 1.

Optionally, a prolonged scanning period may be an integer multiple ofthe scanning period, and is not greater than a preset maximum scanninginterval.

According to the method for accessing an access point by a stationdevice provided in this embodiment, a station device selects a masteraccess point from multiple access points according to channel qualityand accesses the master access point, and sends information aboutremaining access points to the master access point, so that the masteraccess point selects a slave access point according to the informationabout the remaining access points. In this way, the master access pointcoordinates with the slave access point to perform data transmissionwith the station device, which improves usage efficiency of spectrumresources, and increases a network throughput.

FIG. 4 is a flowchart of a method for accessing an access point by astation device according to another embodiment. The method described inthis embodiment is a processing procedure on a master access point sidein the embodiment shown in FIG. 4, and includes the following steps.

Step 21: A master access point receives information, which is sent by astation device accessing the master access point, about remaining accesspoints in multiple access points except the master access point, wherethe master access point is determined by the station device according tochannel quality information of the multiple access points that isacquired by the station device.

Step 22: The master access point selects a slave access point from theremaining access points according to the information about the remainingaccess points.

Step 23: The master access point coordinates with the slave access pointto perform data transmission with the station device.

Optionally, before the master access point coordinates with the slaveaccess point to perform data transmission with the station device, aninterface that is for exchange of coordination information isestablished between the master access point and the slave access point,so that the master access point coordinates with the slave access pointto perform data transmission with the station device.

Optionally, after the master access point selects the slave access pointfrom the remaining access points according to the information about theremaining access points, the master access point may further updatelocal second coordination cluster information, where the secondcoordination cluster information includes information about the stationdevice and information about the slave access point; the master accesspoint may also send first coordination cluster information to thestation device, where the first coordination cluster informationincludes information about the master access point and the informationabout the slave access point, so that the station device updates localfirst coordination cluster information according to the firstcoordination cluster information, and performs data transmission withthe master access point and the slave access point separately accordingto updated local first coordination cluster information.

According to the method for accessing an access point by a stationdevice provided in this embodiment, a master access point selects aslave access point according to information about remaining accesspoints; in this way, the master access point coordinates with the slaveaccess point to perform data transmission with a station device, whichimproves usage efficiency of spectrum resources, and increases a networkthroughput.

FIG. 5 is a signaling flowchart of selecting a master access point by aSTA in a method for accessing an access point by a station deviceaccording to another embodiment of the present invention. Specificoperation steps of selecting, by a STA, a master AP associated with theSTA include the following steps.

Step 41: A STA scans APs, and acquires channel quality of the multipleAPs.

This embodiment and other embodiments following this embodiment are alldescribed by using an example in which the channel quality is an RSNI.

Step 42: The STA records RSNI information of these APs, for example, theSTA maintains an RSNI list for these APs, and adds all RSNIs that areobtained through measurement to the list.

Step 43: Select an AP having the strongest RSNI from the scanned APs asa master AP.

Step 44: The STA accesses the selected AP, that is, the master AP,according to a normal authentication and association process, whichincludes: the STA sends an authentication request to the master AP, andreceives an authentication response returned by the master AP; the STAthen sends an association request to the master AP, and receives anassociation response returned by the master AP.

If the AP having the strongest RSNI refuses to be accessed by the STA(for example, the AP and the STA are not users in a same network), theSTA selects an AP having the second strongest RSNI and accesses the APhaving the second strongest RSNI. This process is repeated until the STAsuccessfully accesses an AP, which can be accessed by the STA, having abest RSNI.

FIG. 6 is a signaling flowchart of selecting a slave access point in amethod for accessing an access point by a station device according toanother. Specific operation steps of selecting and associating with aslave AP and finally forming a coordination AP cluster include thefollowing steps.

Step 51: A STA (for example, a STA 1) scans a channel, collectsneighboring basic service set (BSS) information, and accesses a masterAP successfully.

Step 52: The STA sends, by sending a report of neighboring APinformation, received information about an AP whose RSNI value is lessthan an RSNI value of the master AP (for example, an AP 1) to the masterAP, where the information about the AP may include a basic service setidentifier (BSSID), a received signal to noise indicator (RSNI), asignal to noise ratio (SNR), and the like.

Step 53: The AP 1 searches, according to the information about the APsent by the STA, for an AP, for example, an AP 2, with which the AP 1can coordinate to communicate with the STA. For example, the AP 1determines whether the AP reported by the STA 1 and the AP 1 are APs ina same network or in a same service set identifier (SSID), and uses, asa slave AP, an AP that belongs to the same network or the same BSS asthe AP 1.

Step 54: The AP 1 establishes an IE-CS interface with the slave AP byusing an interface for exchange of coordination information (IE-CS)setup request (IE-CS Setup Request) message and an IE-CS setup response(IE-CS Setup Response) message, where the interface may be configured toexchange CSI measurement information of the STA.

Step 55: The AP 1 establishes a coordination relationship with the slaveAP by using a coordination request message/coordination responsemessage.

Step 56: After the coordination relationship is established, each of themaster AP and the slave AP upgrades respective coordination clusterinformation, that is, updates the coordination cluster information, forexample, the AP 1 adds the STA 1 to a master STA list of the AP 1, andan AP 2 adds the STA 1 to a slave STA list.

Step 57: The master AP sends a notification of the coordination clusterinformation, and feeds back the coordination cluster information to theSTA 1.

Step 58: The STA 1 upgrades local coordination cluster information, thatis, updates the coordination cluster information, for example, adds theAP 1 to a master AP list, and adds the AP 2 to a slave AP list.

Step 59: The STA 1 sends a response (ACK) message to the master AP, torespond to the coordination cluster information sent by the master AP.

So far, the process of selecting and associating with the master AP bythe STA 1 and establishing the coordination AP cluster by the master APis completed.

FIG. 7 is a flowchart of a method for accessing an access point by astation device according to another embodiment. This embodiment providesa detailed process of periodically scanning access points by a STA. TheSTA may prolong and shorten a scanning period according to a status ofchannel quality of multiple access points that is obtained throughscanning. Specific operation steps include the following steps.

Step 61: A STA acquires beacon period information, where beacons of allAPs are the same, and may be, for example, t_(b). The STA may set ascanning interval change frequency n* and a maximum scanning interval T.In a common situation, T is an integer multiple of t_(b).

Step 62: The STA determines whether there is data to be transmitted; ifyes, perform step 63; otherwise, end the process.

Step 63: When the STA needs to transmit data, a scanning periodt_(s)=j×t_(b) is first defined, where j may be a set integer.

Step 64: Determine whether t_(s) is less than T; if yes, perform step65; otherwise, perform step 66.

Step 65: The STA scans once at a time interval t_(s), to obtain RSNIinformation of multiple APs; then perform step 67.

Step 66: The STA scans once at a time interval T, to obtain RSNIinformation of multiple APs; then perform step 67.

Step 67: The STA performs, according to the obtained RSNI information,processes of selecting a master AP and associating with the master AP,selecting a slave AP, and forming a coordination cluster. For details,reference may be made to corresponding descriptions in the embodimentsin FIG. 3 to FIG. 6, and details are not described herein again.

Step 68: The STA compares channel quality of the multiple APs that isacquired through current scanning with channel quality of multipleaccess points that is acquired through previous scanning.

Step 69: If a change value between the channel quality of the multipleaccess points that is acquired in a current scan and the channel qualityof the multiple access points that is acquired in a previous scan isgreater than or equal to a first set range, set that j=j−1, so as toshorten the scanning period, and then perform step 65; when the STA hasno data transmission requirement or ends current transmission, amaintaining process of the master AP and the slave AP also ends; or, ifchannel quality change values of multiple access points, which areacquired in n consecutive scans, are less than the first set range, setthat j=j+1, so as to prolong the scanning period, and then perform step66.

It should be noted that, when the channel quality of the APs changesrelatively slightly, extra system overhead burden caused by frequentlychanging the master AP and the slave AP can be avoided. When the channelquality changes greatly, the master AP and the slave AP can be changedin time, so as to ensure data transmission of the STA. The first setrange may be set according to actual situations or requirements, forexample, it may be determined whether RSNI values of multiple APsincrease or decrease by a fixed threshold; if an increased value or adecreased value exceeds the threshold, it is considered that the channelquality changes relatively greatly; otherwise, it is considered that thechannel quality changes relatively slightly. In a process of determiningthe change, a change status of channel quality of the master AP in themultiple APs may be used as a reference, a change status of channelquality of the slave AP may also be used as a reference, or a changestatus of channel quality of another one or more APs may be used as areference.

By using a scenario shown in FIG. 8 as an example, an AP 1 and an AP 2are respectively a master AP and a slave AP of a STA 1, and arerespectively a slave AP and a master AP of a STA 2.

As shown in FIG. 9, the AP 1 and the AP 2 send beacons with a fixedperiod. At an initial stage, the STA 1 and the STA 2 perform scanning atan interval of a beacon period, and after it is found by performingscanning for three continuous times that channel quality of the APs doesnot change greatly, the scanning interval becomes three times the lengthof the beacon period. After it is found after scanning is performed forthree continuous times at the new scanning interval that the channelquality of the APs still does not change greatly, the scanning intervalis updated to three times the length of the current scanning intervaltime, such as the STA 1 in FIG. 9. If the channel quality of the APsdoes not change in a relatively long time, after the scanning intervalreaches a maximum value, the maximum value of the scanning intervalremains unchanged until the channel quality of the APs changesrelatively greatly, so as to avoid that the STA cannot respond to achange of the channel quality of the APs in time due to limitlessprolonging of the scanning interval. When the channel quality of the APschanges relatively greatly, the STA resets the scanning interval to thebeacon period, and performs the maintaining process of the master AP andthe slave AP again according to the foregoing steps, for example, theseventh scanning interval of the STA 1 and the fifth scanning intervalof the STA 2 in FIG. 9.

FIG. 10 is a schematic structural diagram of a station device accordingto an embodiment. The device described in this embodiment is configuredto implement the method shown in FIG. 3, and includes: a detector 11,configured to acquire channel quality information of multiple accesspoints. The device also includes a processor 12, configured to determinea master access point from the multiple access points according to thechannel quality information of the multiple access points, and accessthe master access point. The device also includes a transceiver 13,configured to send information about remaining access points in themultiple access points except the master access point to the masteraccess point, so that the master access point determines a slave accesspoint according to the information about the remaining access points andcoordinates with the slave access point to perform data transmissionwith the station device.

Optionally, if the station device does not access the master accesspoint successfully, the processor 12 is further configured to determinethat an access point, whose channel quality is lower than channelquality of only the master access point, in the multiple access pointsis a new master access point and access the new master access point.

Optionally, after sending the information about the remaining accesspoints in the multiple access points except the master access point tothe master access point, the transceiver 11 is further configured toreceive first coordination cluster information sent by the master accesspoint, where the first coordination cluster information includesinformation about the master access point and information about theslave access point. The processor 12 is further configured to updatelocal first coordination cluster information according to the receivedfirst coordination cluster information, so as to perform datatransmission with the master access point and the slave access pointseparately according to updated local first coordination clusterinformation.

Optionally, the detector 11 is specifically configured to periodicallyscan access points according to a preset scanning period t_(s), andacquire the channel quality information of the multiple access points.

Optionally, the processor 12 is specifically configured to: after thechannel quality information of the multiple access points is acquired ata time interval t_(s), reselect a new master access point from themultiple access points and access the new master access point. Thetransceiver 13 is specifically configured to: after the new masteraccess point is reselected at a time interval t_(s) and the new masteraccess point is accessed, send information about remaining access pointsin the multiple access points except the new master access point to thenew master access point.

Optionally, j is a positive integer, and t_(b) is a beacon period.

Optionally, the processor 12 is further configured to: if a change valuebetween channel quality of multiple access points that is acquired in acurrent scan and channel quality of multiple access points that isacquired in a previous scan is greater than or equal to a first setrange, shorten the scanning period; or, if channel quality change valuesof multiple access points, which are acquired in n consecutive scans,are less than the first set range, prolong the scanning period, where nis an integer greater than or equal to 1.

Optionally, a prolonged scanning period is an integer multiple of thescanning period, and is not greater than a preset maximum scanninginterval.

Optionally, the information about the remaining access points mayinclude basic service set identifiers of the remaining access pointsand/or channel quality information of the remaining access points.

Optionally, the channel quality information includes at least one ormore of the following: a received signal to noise indicator (RSNI), areceived signal strength indicator (RSSI), a beacon received signalstrength indicator (Beacon RSSI), a beacon signal to noise ratio (BeaconSNR), a data frame received signal strength indicator (Data Frame RSSI),and a data frame signal to noise ratio (Data Frame SNR).

For a specific execution process of the station device provided in thisembodiment and technical effects thereof, reference may be made torelated descriptions in the embodiments in FIG. 3 and FIG. 5 to FIG. 9,and details are not described herein again.

FIG. 11 is a schematic structural diagram of an embodiment of an accesspoint. As shown in FIG. 1i , the access point includes a transceiver 21,configured to receive information, which is sent by a station deviceaccessing a master access point, about remaining access points inmultiple access points except the master access point, where the masteraccess point is determined by the station device according to channelquality information of the multiple access points that is acquired bythe station device. The access point also includes a processor 22,configured to select a slave access point from the remaining accesspoints according to the information about the remaining access points,where the transceiver 21 is further configured to coordinate with theslave access point to perform data transmission with the station device.

Optionally, before coordinating with the slave access point to performdata transmission with the station device, the transceiver 21 is furtherconfigured to establish an interface, which is for exchange ofcoordination information, between the transceiver 21 and the slaveaccess point.

Optionally, after the transceiver 21 selects the slave access point fromthe remaining access points according to the information about theremaining access points, the processor 22 is further configured toupdate local second coordination cluster information, where the secondcoordination cluster information includes information about the stationdevice and information about the slave access point; and the transceiver21 is further configured to send first coordination cluster informationto the station device, where the first coordination cluster informationincludes information about the master access point and the informationabout the slave access point, so that the station device updates localfirst coordination cluster information according to the firstcoordination cluster information, and performs data transmission withthe master access point and the slave access point separately accordingto updated local first coordination cluster information.

Optionally, the information about the remaining access points mayinclude basic service set identifiers of the remaining access pointsand/or channel quality information of the remaining access points; andthe processor 22 may be specifically configured to select an accesspoint, which is in a same basic service set, as the slave access pointaccording to the basic service set identifiers of the remaining accesspoints.

Optionally, the channel quality information includes at least one ormore of the following: a received signal to noise indicator (RSNI), areceived signal strength indicator (RSSI), a beacon received signalstrength indicator (Beacon RSSI), a beacon signal to noise ratio (BeaconSNR), a data frame received signal strength indicator (Data Frame RSSI),and a data frame signal to noise ratio (Data Frame SNR).

The access point provided in this embodiment is configured to performthe methods involved in the embodiments shown in FIG. 4 to FIG. 9. For aspecific execution process of the access point and technical effectsthereof, reference may be made to related descriptions in the methodembodiments, and details are not described herein again.

FIG. 12 is a schematic structural diagram of a station device accordingto another embodiment of the present invention. The device described inthis embodiment is configured to implement the method shown in FIG. 3,and includes: a detection module 31, configured to acquire channelquality information of multiple access points; a processing module 32,configured to determine a master access point from the multiple accesspoints according to the channel quality information of the multipleaccess points, and access the master access point; and a transceivermodule 33, configured to send information about remaining access pointsin the multiple access points except the master access point to themaster access point, so that the master access point determines a slaveaccess point according to the information about the remaining accesspoints and coordinates with the slave access point to perform datatransmission with the station device.

Optionally, if the station device does not access the master accesspoint successfully, the processing module 32 is further configured todetermine that an access point, whose channel quality is lower thanchannel quality of only the master access point, in the multiple accesspoints is a new master access point and access the new master accesspoint.

Optionally, after sending the information about the remaining accesspoints in the multiple access points except the master access point tothe master access point, the transceiver module 33 is further configuredto receive first coordination cluster information sent by the masteraccess point, where the first coordination cluster information includesinformation about the master access point and information about theslave access point; and the processing module 32 is further configuredto update local first coordination cluster information according to thereceived first coordination cluster information, so as to perform datatransmission with the master access point and the slave access pointseparately according to updated local first coordination clusterinformation.

Optionally, the detection module 31 is specifically configured toperiodically scan access points according to a preset scanning periodt_(s), and acquire the channel quality information of the multipleaccess points.

Optionally, the processing module 32 is specifically configured to:after the channel quality information of the multiple access points isacquired at a time interval t_(s), reselect a new master access pointfrom the multiple access points and access the new master access point;and the transceiver module 33 is specifically configured to: after thenew master access point is reselected at a time interval t_(s) and thenew master access point is accessed, send information about remainingaccess points in the multiple access points except the new master accesspoint to the new master access point.

Optionally, j is a positive integer, and t_(b) is a beacon period.

Optionally, the processing module 32 is further configured to: if achange value between channel quality of multiple access points that isacquired in a current scan and channel quality of multiple access pointsthat is acquired in a previous scan is greater than or equal to a firstset range, shorten the scanning period; or, if channel quality changevalues of multiple access points, which are acquired in n consecutivescans, are less than the first set range, prolong the scanning period,where n is an integer greater than or equal to 1.

Optionally, a prolonged scanning period is an integer multiple of thescanning period, and is not greater than a preset maximum scanninginterval.

Optionally, the information about the remaining access points mayinclude basic service set identifiers of the remaining access pointsand/or channel quality information of the remaining access points.

Optionally, the channel quality information includes at least one ormore of the following: a received signal to noise indicator (RSNI), areceived signal strength indicator (RSSI), a beacon received signalstrength indicator (Beacon RSSI), a beacon signal to noise ratio (BeaconSNR), a data frame received signal strength indicator (Data Frame RSSI),and a data frame signal to noise ratio (Data Frame SNR).

For a specific execution process of the station device provided in thisembodiment and technical effects thereof, reference may be made torelated descriptions in the method embodiments in FIG. 3 and FIG. 5 toFIG. 9, and details are not described herein again.

FIG. 13 is a schematic structural diagram of an embodiment of an accesspoint. As shown in FIG. 13, the access point includes: a transceivermodule 41, configured to receive information, which is sent by a stationdevice accessing a master access point, about remaining access points inmultiple access points except the master access point, where the masteraccess point is determined by the station device according to channelquality information of the multiple access points that is acquired bythe station device; and a processing module 42, configured to select aslave access point from the remaining access points according to theinformation about the remaining access points, where the transceivermodule 41 is further configured to coordinate with the slave accesspoint to perform data transmission with the station device.

Optionally, before coordinating with the slave access point to performdata transmission with the station device, the transceiver module 41 isfurther configured to establish an interface, which is for exchange ofcoordination information, between the transceiver module 41 and theslave access point.

Optionally, after the transceiver 21 selects the slave access point fromthe remaining access points according to the information about theremaining access points, the transceiver module 41 is further configuredto update local second coordination cluster information, where thesecond coordination cluster information includes information about thestation device and information about the slave access point; and thetransceiver module 41 is further configured to send first coordinationcluster information to the station device, where the first coordinationcluster information includes information about the master access pointand the information about the slave access point, so that the stationdevice updates local first coordination cluster information according tothe first coordination cluster information, and performs datatransmission with the master access point and the slave access pointseparately according to updated local first coordination clusterinformation.

Optionally, the information about the remaining access points mayinclude basic service set identifiers of the remaining access pointsand/or channel quality information of the remaining access points; andthe transceiver module 41 may be specifically configured to select anaccess point, which is in a same basic service set, as the slave accesspoint according to the basic service set identifiers of the remainingaccess points.

Optionally, the channel quality information includes at least one ormore of the following: a received signal to noise indicator (RSNI), areceived signal strength indicator (RSSI), a beacon received signalstrength indicator (Beacon RSSI), a beacon signal to noise ratio (BeaconSNR), a data frame received signal strength indicator (Data Frame RSSI),and a data frame signal to noise ratio (Data Frame SNR).

The station device provided in this embodiment is configured to performthe methods involved in the embodiments shown in FIG. 4 to FIG. 9. For aspecific execution process of the station device and technical effectsthereof, reference may be made to related descriptions in the methodembodiments, and details are not described herein again.

With descriptions of the foregoing embodiments, persons skilled in theart may clearly understand that the present invention may be implementedby hardware, firmware or a combination thereof. When the presentinvention is implemented by software, the foregoing functions may bestored in a computer-readable medium or transmitted as one or moreinstructions or code in the computer-readable medium. Thecomputer-readable medium includes a computer storage medium and acommunications medium, where the communications medium includes anymedium that enables a computer program to be transmitted from one placeto another. The storage medium may be any available medium accessible toa computer. The following provides an example but does not impose alimitation: The computer-readable medium may include a RAM, a ROM, anEEPROM, a CD-ROM, or another optical disc storage or disk storagemedium, or another magnetic storage device, or any other medium that cancarry or store expected program code in a form of an instruction or adata structure and can be accessed by a computer. In addition, anyconnection may be appropriately defined as a computer-readable medium.For example, if software is transmitted from a website, a server oranother remote source by using a coaxial cable, an optical fiber/cable,a twisted pair, a digital subscriber line (DSL) or wireless technologiessuch as infrared ray, radio and microwave, the coaxial cable, opticalfiber/cable, twisted pair, DSL or wireless technologies such as infraredray, radio and microwave are included in fixation of a medium to whichthey belong. For example, a disk and disc used by the embodimentsincludes a compact disc (CD), a laser disc, an optical disc, a digitalversatile disc (DVD), a floppy disk and a Blu-ray disc, where the diskgenerally copies data by a magnetic means, and the disc copies dataoptically by a laser means. The foregoing combination should also beincluded in the protection scope of the computer-readable medium.

Finally, it should be noted that the foregoing embodiments are merelyintended for describing the technical solutions of the presentinvention, but not for limiting the present invention. Although thepresent invention is described in detail with reference to the foregoingembodiments, persons of ordinary skill in the art should understand thatthey may still make modifications to the technical solutions describedin the foregoing embodiments or make equivalent replacements to some orall technical features thereof, as long as such modifications orreplacements do not cause the essence of corresponding technicalsolutions to depart from the scope of the technical solutions of theembodiments of the present invention.

What is claimed is:
 1. A method, comprising: acquiring, by a stationdevice, channel quality information of a plurality of access points;determining, by the station device, a first master access point from theplurality of access points according to the channel quality informationof the plurality of access points, and accessing the first master accesspoint; and sending, by the station device, information about remainingaccess points in the plurality of access points to the first masteraccess point, the remaining access points comprising the plurality ofaccess points except the first master access point, wherein sending theinformation about the remaining access points to the first master accesspoint causes the first master access point to determine a slave accesspoint according to the information about the remaining access points,and to coordinate with the slave access point to perform datatransmission with the station device.
 2. The method according to claim1, wherein in response to the station device not accessing a secondmaster access point successfully, the station device determines that thefirst master access point is an access point whose channel quality islower than channel quality of only the second master access point in theplurality of access points, and the station device accesses the firstmaster access point.
 3. The method according to claim 1, wherein aftersending the information about the remaining access points in theplurality of access points except the first master access point to thefirst master access point, the method further comprises: receiving, bythe station device, first coordination cluster information sent by thefirst master access point, wherein the first coordination clusterinformation comprises information about the first master access pointand information about the slave access point; and updating, by thestation device, local first coordination cluster information accordingto the received first coordination cluster information, and performingdata transmission with the first master access point and the slaveaccess point separately according to the updated local firstcoordination cluster information.
 4. The method according to claim 3,wherein acquiring the channel quality information of the plurality ofaccess points comprises: periodically scanning, by the station device,the plurality of access points according to a preset scanning periodt_(s), and acquiring the channel quality information of the plurality ofaccess points.
 5. The method according to claim 4, wherein determiningthe first master access point from the plurality of access pointsaccording to the channel quality information, and accessing the firstmaster access point comprises: after acquiring the channel qualityinformation of the plurality of access points, selecting, by the stationdevice, the first master access point from the plurality of accesspoints, and accessing the first master access point; and sending theinformation about the remaining access points in the plurality of accesspoints except the first master access point to the first master accesspoint comprises: after selecting the first master access point andaccessing the first master access point, sending, by the station device,the information about the remaining access points in the plurality ofaccess points except the first master access point to the first masteraccess point.
 6. A method, comprising: receiving, by a first masteraccess point, information which is sent by a station device accessingthe first master access point, wherein the information is aboutremaining access points in a plurality of access points, the remainingaccess points comprising the plurality of access points except the firstmaster access point, wherein the first master access point is determinedby the station device according to channel quality information of theplurality of access points that is acquired by the station device;selecting, by the first master access point, a slave access point fromthe remaining access points according to the information about theremaining access points; and coordinating, by the first master accesspoint, with the slave access point to perform data transmission with thestation device.
 7. The method according to claim 6, wherein beforecoordinating with the slave access point to perform data transmissionwith the station device, the method further comprises: establishing aninterface for exchange of coordination information between the firstmaster access point and the slave access point.
 8. The method accordingto claim 6, wherein after selecting the slave access point from theremaining access points according to the information about the remainingaccess points, the method further comprises: updating, by the firstmaster access point, local second coordination cluster information,wherein the local second coordination cluster information comprisesinformation about the station device and information about the slaveaccess point; and sending, by the first master access point, firstcoordination cluster information to the station device, wherein thefirst coordination cluster information comprises information about thefirst master access point and the information about the slave accesspoint, and wherein sending the first coordination cluster informationcauses the station device to update local first coordination clusterinformation according to the received first coordination clusterinformation, and to perform data transmission with the first masteraccess point and the slave access point according to the updated localfirst coordination cluster information.
 9. The method according to claim6, wherein the information about the remaining access points comprisesbasic service set identifiers of the remaining access points or channelquality information of the remaining access points; and wherein when theinformation about the remaining access points comprises the basicservice set identifiers of the remaining access points, selecting, bythe first master access point, the slave access point from the remainingaccess points according to the information about the remaining accesspoints comprises: selecting, by the first master access point, an accesspoint which is in a same basic service set as the slave access pointaccording to the basic service set identifiers of the remaining accesspoints.
 10. The method according to claim 6, wherein the channel qualityinformation comprises: a received signal to noise indicator (RSNI), areceived signal strength indicator (RSSI), a beacon received signalstrength indicator (Beacon RSSI), a beacon signal to noise ratio (BeaconSNR), a data frame received signal strength indicator (Data Frame RSSI),or a data frame signal to noise ratio (Data Frame SNR).
 11. A stationdevice, comprising: a transceiver, configured to acquire channel qualityinformation of a plurality of access points; a processor; and acomputer-readable storage medium storing a program to be executed by theprocessor, the program including instructions for: determining a firstmaster access point from the plurality of access points according to thechannel quality information of the plurality of access points, andaccessing the first master access point; and wherein the transceiver isfurther configured to: send information about remaining access points tothe first master access point, the remaining access points comprisingthe plurality of access points except the first master access point,wherein sending the information about the remaining access points to thefirst master access point causes the first master access point todetermine a slave access point according to the information about theremaining access points, and to coordinate with the slave access pointto perform data transmission with the station device.
 12. The stationdevice according to claim 11, wherein the program further includesinstructions for: when the station device does not access a secondmaster access point successfully, determine that an access point whosechannel quality is lower than channel quality of only the second masteraccess point in the plurality of access points is the first masteraccess point, and access the first master access point.
 13. The stationdevice according to claim 11, wherein after sending the informationabout the remaining access points in the plurality of access pointsexcept the first master access point to the first master access point,the transceiver is further configured to: receive first coordinationcluster information sent by the first master access point, wherein thefirst coordination cluster information comprises information about thefirst master access point and information about the slave access point;and wherein the program further includes instructions for updating localfirst coordination cluster information according to the received firstcoordination cluster information, and performing data transmission withthe first master access point and the slave access point separatelyaccording to the updated local first coordination cluster information.14. The station device according to claim 13, wherein the transceiverbeing configured to acquire the channel quality information of theplurality of access points comprises the transceiver being configured toperiodically scan the plurality of access points according to a presetscanning period t_(s), and acquire the channel quality information ofthe plurality of access points.
 15. The station device according toclaim 14, wherein the program further includes instructions for: afterthe channel quality information of the plurality of access points isacquired, selecting the first master access point from the plurality ofaccess points, and accessing the first master access point; and whereinthe transceiver is further configured to: after the first master accesspoint is selected and the first master access point is accessed, sendinformation about the remaining access points in the plurality of accesspoints except the first master access point to the first master accesspoint.
 16. An access point, configured to act as a first master accesspoint, the access point comprising: a transceiver, configured to receiveinformation, which is sent by a station device accessing the firstmaster access point, wherein the information is about remaining accesspoints in a plurality of access points, the remaining access pointscomprising the plurality of access points except the first master accesspoint, wherein the first master access point is determined by thestation device according to channel quality information of the pluralityof access points that is acquired by the station device; and aprocessor; and a computer-readable storage medium storing a program tobe executed by the processor, the program including instructions for:selecting a slave access point from the remaining access pointsaccording to the information about the remaining access points; whereinthe transceiver is further configured to coordinate with the slaveaccess point to perform data transmission with the station device. 17.The access point according to claim 16, wherein before coordinating withthe slave access point to perform data transmission with the stationdevice, the transceiver is further configured to establish an interfacefor exchange of coordination information between the transceiver and theslave access point.
 18. The access point according to claim 16, whereinthe program further includes instructions for: after the slave accesspoint is selected from the remaining access points according to theinformation about the remaining access points, updating local secondcoordination cluster information, wherein the local second coordinationcluster information comprises information about the station device andinformation about the slave access point; and wherein the transceiver isfurther configured to send first coordination cluster information to thestation device, wherein the first coordination cluster informationcomprises information about the first master access point and theinformation about the slave access point, wherein sending the firstcoordination cluster information to the station device causes thestation device to update local first coordination cluster informationaccording to the received first coordination cluster information, and toperform data transmission with the first master access point and theslave access point separately according to the updated local firstcoordination cluster information.
 19. The access point according toclaim 16, wherein the information about the remaining access pointscomprises basic service set identifiers of the remaining access pointsor channel quality information of the remaining access points; andwherein the program further includes instructions for selecting anaccess point which is in a same basic service set as the slave accesspoint according to the basic service set identifiers of the remainingaccess points.
 20. The access point according to claim 16, wherein thechannel quality information comprises: a received signal to noiseindicator (RSNI), a received signal strength indicator (RSSI), a beaconreceived signal strength indicator (Beacon RSSI), a beacon signal tonoise ratio (Beacon SNR), a data frame received signal strengthindicator (Data Frame RSSI), or a data frame signal to noise ratio (DataFrame SNR).